Lighting apparatus and lighting system including the same

ABSTRACT

A lighting apparatus including a controller and an LED luminaire to implement a color temperature from a minimum of 3,000K or less to a maximum of 5,000K or more, the LED luminaire including at least one first light emitter, at least one second light emitter, and at least one third light emitter, in which a triangle region defined by color coordinates of the light emitters includes at least a region on a Planckian locus, and the maximum and minimum color temperatures in the triangle region are 5,000K or more, and 3,000K or less, respectively, and in the CIE-1931 coordinate system, the color coordinates of the first light emitter is closer to 5,000K than those of the second and third light emitters, and the color coordinates of the third light emitter is closer to 3,000K than those of the first and second light emitters.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.18/092,335, filed on Jan. 1, 2023, which is a Continuation of U.S.patent application Ser. No. 17/392,160 filed on Aug. 2, 2021, now issuedas U.S. Pat. No. 11,546,978, which is a Continuation of U.S. patentapplication Ser. No. 16/698,836, filed on Nov. 27, 2019, now issued asU.S. Pat. No. 11,083,060, which claims the benefit of U.S. ProvisionalApplication No. 62/773,364, filed on Nov. 30, 2018, and U.S. ProvisionalApplication No. 62/776,098, filed on Dec. 6, 2018, each of which ishereby incorporated by reference for all purposes as if fully set forthherein.

BACKGROUND Field

Exemplary embodiments relate to a lighting apparatus and a lightingsystem, and more particularly, to a lighting apparatus using a lightemitting diode as a light source, and a lighting system including thesame.

Discussion of the Background

Most life on earth has adapted to work in tune with the sun. The humanbody has also adapted to sunlight over a long period of time.Accordingly, human circadian biorhythm is known to change with thechange of sunlight. More particularly, in the morning, cortisol issecreted from the human body under bright sunlight. Cortisol causes moreblood to be supplied to the organs of the body to increase the pulse andrespiration in response to external stimulus, such as stress, therebycausing the body to awaken and prepare for daytime activity. Afteractive physical activity under active sunlight during the daytime, thebody secretes melatonin in the evening to reduce the pulse, bodytemperature, and blood pressure of the body, thereby assisting inresting and sleeping.

In modern society, however, most people mainly perform physicalactivities at home or in the office instead of under sunlight. It iscommon that the time staying indoors in the afternoon is longer than thetime for physical activity under sunlight.

However, indoor lighting apparatuses generally exhibit a constantspectral power distribution that significantly differs from the spectralpower distribution of sunlight. For example, although a light emittingapparatus using blue, green, and red light emitting diodes can implementwhite light through combination of a blue color, a green color, and ared color, the light emitting apparatus exhibits a spectral powerdistribution having peak at a particular wavelength, rather than thespectral power distribution over a broad wavelength spectrum of visiblelight as in sunlight.

FIG. 1 is a graph depicting a spectral power distribution of black bodyradiation corresponding to several color temperatures on a Planckianlocus in the CIE color coordinate system, and FIG. 2 is a graphdepicting spectral power distributions of white light sources based ontypical blue light emitting diode chips corresponding to severalcorrelated color temperatures.

Referring to FIG. 1 and FIG. 2 , the spectrum of black body radiationlike the sun shows higher intensity in the blue wavelength region withincreasing color temperature, as in the spectrum of a typical whitelight source. However, as color temperature increases, the differencebetween the spectrum of the white light source and the spectrum of theblack body radiation becomes clearer. For example, the spectrum of theblack body radiation at a temperature of 6,500K shows that the intensityof light gradually decreases from the blue wavelength region to the redwavelength region. However, as shown in FIG. 2 , in the white lightingapparatus based on the blue light emitting diode chips, the intensity oflight in the blue wavelength region becomes stronger with increasingcolor temperature.

The human eye lens adapted to the spectrum of sunlight can be damaged byabnormally strong light in the blue wavelength region, thereby causingpoor eyesight. Moreover, when retinal cells are exposed to excessiveenergy in the blue wavelength region, abnormal signals can betransmitted to the brain to abnormally promote or suppress generation ofhormones, such as cortisol and melatonin, thereby having a negativeeffect on the body's circadian rhythm.

The above information disclosed in this Background section is only forunderstanding of the background of the inventive concepts, and,therefore, it may contain information that does not constitute prior art

SUMMARY

Exemplary embodiments provide a lighting apparatus and a lighting systemcapable of changing a spectrum power distribution thereof automaticallyin accordance with a change in spectrum power distribution of sunlight.

Exemplary embodiments also provide a lighting apparatus and a lightingsystem capable of preventing or relieving damage to the eye lens orretina of a user by light in an abnormal blue wavelength region.

Exemplary embodiments further provide a lighting apparatus and alighting system capable of maintaining stable operation based on actualtime even when an external power source is blocked.

Additional features of the inventive concepts will be set forth in thedescription which follows, and in part will be apparent from thedescription, or may be learned by practice of the inventive concepts.

A lighting apparatus according to an exemplary embodiment includes: acontroller; an LED driver; and an LED luminaire, in which the LEDluminaire implements a color temperature from a minimum colortemperature of 3,000K or less to a maximum color temperature of 5,000Kor more, and the controller controls the LED driver to change the colortemperature of the LED luminaire to correspond to change in colortemperature of sunlight.

Accordingly, a lighting apparatus may have a variable color temperaturelike sunlight throughout a daily cycle.

The maximum color temperature may be 6,000K or more and the minimumcolor temperature may be 2,700K or less. Furthermore, the maximum colortemperature may be 6,500K or more.

The lighting apparatus may further include an RTC (real time clock), bywhich the lighting apparatus may allow change of the color temperatureaccording to a color temperature schedule of the luminaire even withoutinput of an external signal.

The RTC may be embedded in the controller.

The lighting apparatus may further include RTC power supply.

The RTC power supply may include a super capacitor, such that the RTCcan be stably operated for a long period of time even under conditionswhere temperature increases due to operation of the lighting apparatus.

The controller may control the luminaire to automatically change thecolor temperature of light emitted therefrom in accordance with the RTCto correspond to the color temperature of sunlight.

The lighting apparatus may automatically adjust the color temperatureand brightness of light emitted from the luminaire for a day withoutexternal input.

The LED luminaire may include a light emitting apparatus, which mayinclude: at least one first light emitting unit including a UV, violet,or blue light emitting diode chip and a first wavelength converter; atleast one second light emitting unit including a UV, violet, or bluelight emitting diode chip and a second wavelength converter; and atleast one third light emitting unit including a UV, violet, or bluelight emitting diode chip and a third wavelength converter, in which atriangle region defined by color coordinates of the first light emittingunit, the second light emitting unit and the third light emitting unitincludes at least some section on a Planckian locus, and the maximumcolor temperature and the minimum color temperature on the Planckianlocus included in the triangle region may be 5,000K or more and 3,000Kor less, respectively.

Hereinafter, unless specifically stated otherwise, the Planckian locusand certain color coordinates may refer to the Planckian locus and colorcoordinates in the CIE-1931 coordinate system regulated by AmericanNational Standards Institute (ANSI), respectively. The CIE-1931coordinate system can be easily converted into the 1976 coordinatesystem through simple numerical modification.

The first to third light emitting units may employ a UV or violet lightemitting diode chip only.

The first and second light emitting units may employ a UV or violetlight emitting diode chip only, and the third light emitting unit mayemploy a UV, violet or blue light emitting diode chip. The third lightemitting unit may have color coordinates approaching a red color, andthus, may emit lower intensity blue light than the first and secondlight emitting units.

When the first to third light emitting units do not employ a blue lightemitting diode chip or the intensity of light emitted from the bluelight emitting diode chip is reduced, the light emitting apparatus canprevent the eye lens or retina of a user from being damaged by light inthe blue wavelength band. Furthermore, the light emitting apparatus canimplement a color temperature in the range of 3,000K to 5,000K on thePlanckian locus, thereby enabling change of the spectrum powerdistribution thereof corresponding to change in spectrum powerdistribution of sunlight.

When the maximum color temperature is increased and the minimum colortemperature is reduced, the lighting apparatus may implement light moresimilar to the spectrum of sunlight. For example, the maximum colortemperature on the Planckian locus included in the triangle region maybe 6,000K or more and the minimum color temperature thereon may be2,700K or less. Furthermore, the maximum color temperature may be 6,500Kor more. Furthermore, the maximum color temperature may be 10,000K ormore and the minimum color temperature may be 1,800K or less.

The color coordinates of the second light emitting unit may be placedabove the Planckian locus in the CIE-1931 coordinate system, the colorcoordinates of the first light emitting unit may be closer to a colortemperature of 5,000K than those of the second and third light emittingunits, and the color coordinates of the third light emitting unit may becloser to a color temperature of 3,000K than those of the first andsecond light emitting units.

The first, second, and third light emitting units may be configured tobe driven in a dimming manner, such that the color temperatures on thePlanckian locus included in the triangle region can be consecutivelyimplemented.

The light emitting apparatus may include a plurality of first lightemitting units, a plurality of second light emitting units, and aplurality of third light emitting units. With the plurality of lightemitting units, the light emitting apparatus can increase light outputtherefrom.

A lighting system according to another exemplary embodiment includes: alighting apparatus; and an electronic control unit adapted to input asignal to the lighting apparatus, in which the lighting apparatusincludes a controller, an LED driver, and an LED luminaire, the LEDluminaire implements a color temperature from a minimum colortemperature of 3,000K or less to a maximum color temperature of 5,000Kor more, and the controller controls the LED driver to change the colortemperature of the LED luminaire corresponding to change in colortemperature of sunlight.

The electronic control unit may include a remote controller, a mobileapplication, a PC or a server. With the electronic control unit, thelighting apparatus may be operated in various modes.

The lighting apparatus may automatically change the color temperature ofthe LED luminaire corresponding to change in color temperature ofsunlight, with the electronic control unit turned off.

The lighting system may further include an RTC embedded in the lightingapparatus.

The lighting apparatus may further include RTC power supply.

In addition, the RTC power supply may include a super capacitor.

With the RTC embedded in the lighting apparatus, the lighting apparatuscan change the color temperature over time without input signals by theelectronic control unit. In addition, since the lighting apparatus isprovided with the RTC power supply, thereby maintaining stable operationbased on actual time through supply of power to the RTC even when anexternal power source is in a turned-off state.

The lighting apparatus may further include a memory storing a colortemperature change scenario according to time in each season.Accordingly, the lighting apparatus can provide various colortemperature changes per season.

The maximum color temperature may be 6,500K or more and the minimumcolor temperature may be 2,700K or less. Accordingly, the lightingapparatus may automatically change the color temperature at least in therange of 2,700K to 6,500K.

The LED luminaire may include a light emitting apparatus, which mayinclude at least one first light emitting unit including a UV, violet,or blue light emitting diode chip and a first wavelength converter; atleast one second light emitting unit including a UV, violet, or bluelight emitting diode chip and a second wavelength converter; and atleast one third light emitting unit including a UV, violet, or bluelight emitting diode chip and a third wavelength converter, in which atriangle region defined by color coordinates of the first light emittingunit, the second light emitting unit and the third light emitting unitincludes at least some section on the Planckian locus, and the maximumcolor temperature and the minimum color temperature on the Planckianlocus included in the triangle region may be 5,000K or more and 3,000Kor less, respectively.

Furthermore, the maximum color temperature on the Planckian locusincluded in the triangle region may be 6,500K or more and the minimumcolor temperature thereon may be 2,700K or less. Furthermore, the firstto third light emitting units may be configured to operate in a dimmingmanner.

The light emitting apparatus may further include a base, and the firstto third light emitting units may be regularly arranged on the base. Thefirst light emitting units, the second light emitting units and thethird light emitting units may be arranged in a row or in a matrix.

The first light emitting unit, the second light emitting unit and thethird light emitting unit may constitute one group, and the first tothird light emitting units in one group may be arranged to form atriangle.

The first to third light emitting units may be arranged such that agroup adjacent to one group constituting a triangle constitutes aninverted triangle.

A distance between adjacent first light emitting units, a distancebetween adjacent second light emitting units, and a distance betweenadjacent third light emitting units may be the same.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph depicting a spectral power distribution of black bodyradiation corresponding to several color temperatures on a Planckianlocus in the CIE color coordinate system.

FIG. 2 is a graph depicting spectral power distributions of white lightsources based on typical blue light emitting diode chips correspondingto several correlated color temperatures.

FIG. 3 is a schematic plan view of a light emitting apparatus accordingto an exemplary embodiment.

FIG. 4 is a schematic cross-sectional view of a light emitting unitaccording to an exemplary embodiment.

FIG. 5 is a schematic cross-sectional view of a light emitting unitaccording to another exemplary embodiment.

FIG. 6 is a graph depicting spectrum power distributions of variouslight emitting units according to exemplary embodiments.

FIG. 7 is a schematic color coordinate graph of a light emittingapparatus according to an exemplary embodiment.

FIG. 8 is a schematic plan view of a light emitting unit according toyet another exemplary embodiment.

FIG. 9 is a schematic color coordinate graph of a light emittingapparatus of FIG. 8 .

FIG. 10 is a schematic color coordinate graph of a light emittingapparatus according to another exemplary embodiment.

FIG. 11 is a schematic color coordinate graph of a light emittingapparatus according to another exemplary embodiment.

FIG. 12 is a schematic plan view of a light emitting apparatus accordingto yet another exemplary embodiment.

FIG. 13 is a schematic plan view of a light emitting apparatus accordingto yet another exemplary embodiment.

FIG. 14 is a schematic plan view of a light emitting apparatus accordingto yet another exemplary embodiment.

FIG. 15 is a schematic color coordinate graph of a light emittingapparatus according to yet another exemplary embodiment.

FIG. 16 is a graph depicting spectrum power distributions of lightemitting units according to an exemplary embodiment.

FIGS. 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, and 28 are graphscomparing various spectra implemented using the light emitting units ofFIG. 16 with the spectrum of black body radiation (reference lightsource) at correlated color temperatures corresponding thereto.

FIG. 29 is a schematic block diagram of a lighting system according toan exemplary embodiment.

FIG. 30 is a schematic block diagram of a lighting system according toanother exemplary embodiment.

FIG. 31 is a schematic block diagram of a lighting system according to afurther exemplary embodiment.

DETAILED DESCRIPTION

In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of various exemplary embodiments or implementations of theinvention. As used herein “embodiments” and “implementations” areinterchangeable words that are non-limiting examples of devices ormethods employing one or more of the inventive concepts disclosedherein. It is apparent, however, that various exemplary embodiments maybe practiced without these specific details or with one or moreequivalent arrangements. In other instances, well-known structures anddevices are shown in block diagram form in order to avoid unnecessarilyobscuring various exemplary embodiments. Further, various exemplaryembodiments may be different, but do not have to be exclusive. Forexample, specific shapes, configurations, and characteristics of anexemplary embodiment may be used or implemented in another exemplaryembodiment without departing from the inventive concepts.

Unless otherwise specified, the illustrated exemplary embodiments are tobe understood as providing exemplary features of varying detail of someways in which the inventive concepts may be implemented in practice.Therefore, unless otherwise specified, the features, components,modules, layers, films, panels, regions, and/or aspects, etc.(hereinafter individually or collectively referred to as “elements”), ofthe various embodiments may be otherwise combined, separated,interchanged, and/or rearranged without departing from the inventiveconcepts.

The use of cross-hatching and/or shading in the accompanying drawings isgenerally provided to clarify boundaries between adjacent elements. Assuch, neither the presence nor the absence of cross-hatching or shadingconveys or indicates any preference or requirement for particularmaterials, material properties, dimensions, proportions, commonalitiesbetween illustrated elements, and/or any other characteristic,attribute, property, etc., of the elements, unless specified. Further,in the accompanying drawings, the size and relative sizes of elementsmay be exaggerated for clarity and/or descriptive purposes. When anexemplary embodiment may be implemented differently, a specific processorder may be performed differently from the described order. Forexample, two consecutively described processes may be performedsubstantially at the same time or performed in an order opposite to thedescribed order. Also, like reference numerals denote like elements.

When an element, such as a layer, is referred to as being “on,”“connected to,” or “coupled to” another element or layer, it may bedirectly on, connected to, or coupled to the other element or layer orintervening elements or layers may be present. When, however, an elementor layer is referred to as being “directly on,” “directly connected to,”or “directly coupled to” another element or layer, there are nointervening elements or layers present. To this end, the term“connected” may refer to physical, electrical, and/or fluid connection,with or without intervening elements. Further, the D1-axis, the D2-axis,and the D3-axis are not limited to three axes of a rectangularcoordinate system, such as the x, y, and z-axes, and may be interpretedin a broader sense. For example, the D1-axis, the D2-axis, and theD3-axis may be perpendicular to one another, or may represent differentdirections that are not perpendicular to one another. For the purposesof this disclosure, “at least one of X, Y, and Z” and “at least oneselected from the group consisting of X, Y, and Z” may be construed as Xonly, Y only, Z only, or any combination of two or more of X, Y, and Z,such as, for instance, XYZ, XYY, YZ, and ZZ. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

Although the terms “first,” “second,” etc. may be used herein todescribe various types of elements, these elements should not be limitedby these terms. These terms are used to distinguish one element fromanother element. Thus, a first element discussed below could be termed asecond element without departing from the teachings of the disclosure.

Spatially relative terms, such as “beneath,” “below,” “under,” “lower,”“above,” “upper,” “over,” “higher,” “side” (e.g., as in “sidewall”), andthe like, may be used herein for descriptive purposes, and, thereby, todescribe one elements relationship to another element(s) as illustratedin the drawings. Spatially relative terms are intended to encompassdifferent orientations of an apparatus in use, operation, and/ormanufacture in addition to the orientation depicted in the drawings. Forexample, if the apparatus in the drawings is turned over, elementsdescribed as “below” or “beneath” other elements or features would thenbe oriented “above” the other elements or features. Thus, the exemplaryterm “below” can encompass both an orientation of above and below.Furthermore, the apparatus may be otherwise oriented (e.g., rotated 90degrees or at other orientations), and, as such, the spatially relativedescriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments and is not intended to be limiting. As used herein, thesingular forms, “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. Moreover,the terms “comprises,” “comprising,” “includes,” and/or “including,”when used in this specification, specify the presence of statedfeatures, integers, steps, operations, elements, components, and/orgroups thereof, but do not preclude the presence or addition of one ormore other features, integers, steps, operations, elements, components,and/or groups thereof. It is also noted that, as used herein, the terms“substantially,” “about,” and other similar terms, are used as terms ofapproximation and not as terms of degree, and, as such, are utilized toaccount for inherent deviations in measured, calculated, and/or providedvalues that would be recognized by one of ordinary skill in the art.

Various exemplary embodiments are described herein with reference tosectional and/or exploded illustrations that are schematic illustrationsof idealized exemplary embodiments and/or intermediate structures. Assuch, variations from the shapes of the illustrations as a result, forexample, of manufacturing techniques and/or tolerances, are to beexpected. Thus, exemplary embodiments disclosed herein should notnecessarily be construed as limited to the particular illustrated shapesof regions, but are to include deviations in shapes that result from,for instance, manufacturing. In this manner, regions illustrated in thedrawings may be schematic in nature and the shapes of these regions maynot reflect actual shapes of regions of a device and, as such, are notnecessarily intended to be limiting.

As is customary in the field, some exemplary embodiments are describedand illustrated in the accompanying drawings in terms of functionalblocks, units, and/or modules. Those skilled in the art will appreciatethat these blocks, units, and/or modules are physically implemented byelectronic (or optical) circuits, such as logic circuits, discretecomponents, microprocessors, hard-wired circuits, memory elements,wiring connections, and the like, which may be formed usingsemiconductor-based fabrication techniques or other manufacturingtechnologies. In the case of the blocks, units, and/or modules beingimplemented by microprocessors or other similar hardware, they may beprogrammed and controlled using software (e.g., microcode) to performvarious functions discussed herein and may optionally be driven byfirmware and/or software. It is also contemplated that each block, unit,and/or module may be implemented by dedicated hardware, or as acombination of dedicated hardware to perform some functions and aprocessor (e.g., one or more programmed microprocessors and associatedcircuitry) to perform other functions. Also, each block, unit, and/ormodule of some exemplary embodiments may be physically separated intotwo or more interacting and discrete blocks, units, and/or moduleswithout departing from the scope of the inventive concepts. Further, theblocks, units, and/or modules of some exemplary embodiments may bephysically combined into more complex blocks, units, and/or moduleswithout departing from the scope of the inventive concepts.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure is a part. Terms,such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and should not be interpreted in anidealized or overly formal sense, unless expressly so defined herein.

FIG. 3 is a schematic plan view of a light emitting apparatus accordingto an exemplary embodiment, and FIG. 4 is a schematic cross-sectionalview of a light emitting unit according to an exemplary embodiment.

Referring to FIG. 3 , a light emitting apparatus 100 includes a base110, a first light emitting unit 122, a second light emitting unit 124,and a third light emitting unit 126.

As in a printed circuit board, the base 110 may include circuit wires tosupply power to each of the light emitting units 122, 124, 126. Inaddition, an integrated circuit element may be mounted on the base 110.

The first to third light emitting units 122, 124, 126 may be arranged onthe base 110. A plurality of first light emitting units 122, a pluralityof second light emitting units 124, and a plurality of third lightemitting units 126 may be arranged on the base 110. Further, as shown inFIG. 3 , the first to third light emitting units 122, 124, 126 may berepeatedly arranged as a group in a row.

Although the light emitting apparatus 100 of FIG. 3 is illustrated asincluding three different types of light emitting units 122, 124, 126arranged on the base 110, the inventive concepts are not limitedthereto. For example, in some exemplary embodiments, two types or fouror more types of light emitting units may be arranged on the base.

The first to third light emitting units 122, 124, 126 may have a similarstructure, and each of the first to third light emitting units 122, 124,126 generally emits light corresponding to a certain color temperatureon the Planckian locus. The structure of each of the light emittingunits will be described in more detail with reference to FIG. 4 .

Referring to FIG. 4 , each of the light emitting units 122, 124, 126includes a light emitting diode chip 23 and a wavelength converter 25,and may further include a housing 21 and a molding member 27.

The housing 21 may have leads for electrical connection and a cavity.

The light emitting diode chip 23 may be mounted inside the cavity of thehousing 21, and is electrically connected to the leads. In general, thelight emitting diode chip 23 may be a lateral type light emitting diodechip, and thus, may be electrically connected to the leads by bondingwires.

The light emitting diode chip 23 may emit light having a peak wavelengthin the range of 300 nm to 470 nm. For example, the light emitting diodechip 23 may be a blue light emitting diode chip, a violet light emittingdiode chip, or a UV light emitting diode chip. In one exemplaryembodiment, the light emitting diode chip 23 may emit light having apeak wavelength in the range of 300 nm to 440 nm, specifically 380 nm to440 nm, more specifically 400 nm to 420 nm.

The first to third light emitting units 122, 124, 126 may include thesame type of light emitting diode chip 23 emitting light having the samepeak wavelength, without being limited thereto. Alternatively, the firstto third light emitting units 122, 124, 126 may include light emittingdiode chips configured to emit light having different peak wavelengthswithin the above range. Each of the first to third light emitting units122, 124, 126 may emit light having a shorter wavelength than thatemitted from a blue light emitting diode chip, and light emitted fromthe first to third light emitting units 122, 124, 126 can have lowerintensity in the blue wavelength region than light emitted from atypical light source. In this case, since most blue light emitted fromthe third light emitting unit 126 is converted into green or red lightthrough wavelength conversion even when the third light emitting unit126 uses the blue light emitting diode chip, the blue light emitted fromthe third light emitting unit 126 may have relatively low intensity.Accordingly, even when the third light emitting unit 126 uses the bluelight emitting diode chip, the blue light emitted from the third lightemitting unit 126 does not damage the retina of a user. As such, in someexemplary embodiments, the first and second light emitting units 122,124 may adopt the UV or violet light emitting diode chip, and the thirdlight emitting unit 126 may adopt the blue light emitting diode chip.

The wavelength converter 25 may be disposed inside the cavity of thehousing 21 and cover the light emitting diode chip 23. The wavelengthconverter 25 converts light emitted from the light emitting diode chip23 into light having a longer wavelength than the wavelength of light.

The wavelength converter 25 may include at least one type of phosphor.With the light emitting diode chip 23 and the wavelength converter 25,the light emitting unit may emit light having a desired colortemperature.

The wavelength converter 25 may include, for example, a blue phosphor, agreen phosphor, a yellow phosphor, or a red phosphor. The blue phosphormay include BAM, halo-phosphate, or aluminate-based phosphors, forexample, BaMgAl₁₀O₁₇:Mn²⁺, BaMgAl₁₂O₁₉:Mn²⁺ or (Sr,Ca,Ba)PO₄Cl:Eu₂₊. Theblue phosphor may have a peak wavelength in the range of, for example,440 nm to 500 nm.

The green or yellow phosphor may include LuAG(Lu₃(Al,Gd)₅O₁₂:Ce³⁺)YAG(Y₃(Al,Gd)₅O₁₂:Ce³⁺), Ga⁻LuAG((Lu,Ga)₃(Al,Gd)₅O₁₂:Ce³⁺), Ga-YAG((Ga,Y)₃(Al,Gd)₅O₁₂:Ce³⁺), LuYAG ((Lu,Y)₃(Al,Gd)₅O₁₂:Ce³⁺),ortho-silicate ((Sr,Ba,Ca,Mg)₂SiO₄:Eu₂₊), oxynitride((Ba,Sr,Ca)Si₂O₂N₂:Eu₂₊), or thiogallate (SrGa₂S₄:Eu²⁺). The green oryellow phosphor may have a peak wavelength in the range of 500 nm to 600nm.

The red phosphor may include nitride, sulfide, fluoride or oxynitridebased phosphors, specifically, CASN (CaAlSiN₃:Eu²⁺),(Ba,Sr,Ca)₂Si₅N₈:Eu²⁺, (Ca,Sr)S₂:Eu²⁺), or (Sr,Ca)₂SiS₄:Eu²⁺. The redphosphor may have a peak wavelength in the range of 600 nm to 700 nm.

The molding member 27 is formed in the cavity of the housing 21 to coverthe wavelength converter 25. The molding member 27 is formed of a lighttransmissive material. For example, the molding member 27 may be formedof methyl silicone or phenyl silicone, specifically phenyl silicone.Although the phenyl silicone is likely to suffer from a yellowingphenomenon upon exposure to UV light, the phenyl silicone has higherstrength than the methyl silicone. In particular, according to anexemplary embodiment, since light emitted from the light emitting diodechip 23 is converted into light having a longer wavelength by thewavelength converter 25, the yellowing phenomenon may not occur, andthus, the light emitting diode chip may employ phenyl silicone.

Although the molding member 27 in FIG. 4 is illustrated as covering thewavelength converter 25, in some exemplary embodiments, the moldingmember 27 may be integrally formed with the wavelength converter 25. Inparticular, the wavelength converter 25 may include the molding membertogether with the phosphor, thereby obviating the need for a separatemolding member covering the wavelength converter.

The light emitting diode chip 23 according to the illustrated exemplaryembodiment is described with reference to a lateral type, which iselectrically connected to the leads by the bonding wires. However, theinventive concepts are not limited thereto. For example, in someexemplary embodiments, the light emitting diode chip 23 may be avertical type or flip chip type light emitting diode chip. In addition,the vertical or flip chip type light emitting diode chip may be mountedinside the cavity of the housing 21. Furthermore, the flip chip typelight emitting diode chip may be directly mounted on the base 110without the housing 21. FIG. 5 exemplarily shows a light emitting unitincluding the flip chip type light emitting diode chip 23 a. Thewavelength converter 25 a may cover upper and side surfaces of the lightemitting diode chip 23 a. Bonding pads are formed on a lower surface ofthe light emitting diode chip 23 a, whereby the light emitting diodechip 23 a having the wavelength converter 25 a thereon can be directlymounted on the base 110 via the bonding pads.

As described above, each of the first to third light emitting units 122,124, 126 emits light corresponding to the color temperature on thePlanckian locus, and this structure will be described in detail withreference to FIG. 6 . FIG. 6 is a graph depicting spectrum powerdistributions of various light emitting units according to exemplaryembodiments.

Referring to FIG. 6 , the spectrum power distributions of light emittingunits configured to emit light having correlated color temperatures from2,700K to 6,500K are shown. Each of the light emitting units includes alight emitting diode chip, which emits light having a shorter wavelengththan that emitted from a blue light emitting diode chip, and awavelength converter, and has an average color rendering index of 95 ormore. The light emitting diode chip may have a peak wavelength of, forexample, about 416 nm, and the phosphors are suitably selected so as toimplement the correlated color temperature of each of the light emittingunits and an average color rendering index of 95 or more.

As shown in FIG. 6 , as the color temperature increases from 2,700K to6,500K, the intensity of light in the blue wavelength region increases.However, since light in the blue wavelength region is emitted from bluephosphors, light does not exhibit abnormally high intensity at aparticular wavelength region. Furthermore, light emitted from thephosphors has higher intensity than light emitted from the lightemitting diode chip.

Accordingly, the light emitting units according to the exemplaryembodiments can reduce the intensity of light in the blue wavelengthregion, as compared with a typical light emitting unit adopting atypical blue light emitting diode chip.

Furthermore, a difference in spectrum between a white light source basedon the typical blue light emitting diode chip and a light source basedon the light emitting units according to the exemplary embodiments canbe clearly confirmed through the fidelity index Rf calculated by IESTM-30-15. Table 1 shows average color rendering indices (CRI) andfidelity indices according to the correlated color temperatures of thelight sources based on the blue light emitting diode chip, and Table 2shows average color rendering indices (CRI) and fidelity indicesaccording to the correlated color temperatures of the light emittingunits according to the exemplary embodiments.

TABLE 1 CRI and fidelity indices of light sources based on a blue lightemitting diode chip and light sources based on a violet light emittingdiode chip. CCT 6,500K 5,700K 5,000K 4,000K 3,000K 2,700K Blue- CRI 96.896.2 96.1 95.6 95.3 96.8 base Rf 91.3 90.6 90.0 89.1 93.3 94.5 Violet-CRI 98.6 98.1 98.1 97.7 97.8 97.2 base Rf 97.7 98.1 98.3 97.7 97.3 96.7

Referring to Table 1, although the typical light sources based on theblue light emitting diode chip have a CRI of 95 or more, the typicallight sources have relatively low fidelity indices. In particular, whilea difference between the CRI and the fidelity index is not large in aregion having a low correlated color temperature, the difference betweenthe CRI and the fidelity index is large in a region having a highcorrelated color temperature.

On the other hand, it can be seen that the violet light emitting diodechip-based light emitting units according to the exemplary embodimentsdo not have a large difference between the CRI and the fidelity index.Accordingly, the light emitting apparatus using the light source basedon the violet light emitting diode chip can emit light similar to actualsunlight.

When the light emitting units according to the exemplary embodiments arearranged in a single light emitting apparatus, it is possible toimplement various color temperatures through the light emittingapparatus.

FIG. 7 is a schematic color coordinate graph of a light emittingapparatus according to an exemplary embodiment. Hereinafter, the lightemitting apparatus will exemplarily be described with reference to theone shown in FIG. 3 including the first to third light emitting units122, 124, 126.

The first to third light emitting units 122, 124, 126 may have colortemperatures of 6,500K, 4,000K and 2,700K, respectively. As describedabove with reference to FIG. 3 , these light emitting units 122, 124,126 may be arranged on the base 110.

The light emitting units 126 having a color temperature of 2,700K mayimplement light that corresponds to sunlight in the morning or in theevening, and the light emitting units 122 having a color temperature of6,500K may implement light that corresponds sunlight of high noon.Further, the light emitting units 124 having a color temperature of4,000K may implement light that corresponds to the middle betweenmorning and high noon or the middle between high noon and evening. Assuch, among the first to third light emitting units 122, 124, 126,particular light emitting units may be operated corresponding to adesired color temperature, thereby allowing change in color temperatureof the light source to correspond to change in the spectrum of sunlightin a daily cycle.

Although the first to third light emitting units 122, 124, 126 aredescribed as having the color temperatures of 6500K, 4000K and 2700K,respectively, the inventive concepts are not limited thereto, and insome exemplary embodiments, the light emitting units may have differentcolor temperatures, and the light emitting units 122, 124, 126 areplaced on the Planckian locus or near the Planckian locus.

In addition, as described above, among the first to third light emittingunits 122, 124, 126, particular light emitting units may be operated toimplement light having a particular color temperature. For example,according to an exemplary embodiment, during operation of the firstlight emitting unit 122, the second and third light emitting units 124,126 are kept in a turned-off state; during operation of the second lightemitting unit 124, the first and third light emitting units 122, 126 arekept in a turned-off state; and during operation of the third lightemitting unit 126, the first and second light emitting units 122, 124are kept in a turned-off state. However, the inventive concepts are notlimited thereto. For example, in some exemplary embodiments, the firstlight emitting unit 122 and the second light emitting unit 124 may beoperated in a dimming manner to implement a correlated color temperaturebetween 6,500K and 4,000K, and the second light emitting unit 124 andthe third light emitting unit 126 may be operated in a dimming manner toimplement a correlated color temperature between 4,000K and 2,700K. Inthis manner, it is possible to implement light that corresponds to mostof the correlated color temperature between 6,500K and 2,700K throughcombination of the first to third light emitting units 122, 124, 126.

FIG. 8 is a schematic plan view of a light emitting apparatus 200according to another exemplary embodiment, and FIG. 9 is a schematiccolor coordinate graph of a light emitting apparatus of FIG. 8 .

Referring to FIG. 8 , the light emitting apparatus 200 according to theillustrated exemplary embodiment is similar to the light emittingapparatus 100 shown in FIG. 3 , except that the light emitting apparatus200 includes two types of light emitting units 222, 224 having differentcolor temperatures. The first light emitting units 222 and the secondlight emitting units 224 are arranged on a base 210. The first lightemitting units 222 and the second light emitting units 224 arealternately arranged.

The base 210 is the same as the base 110 described above, and thus,repeated descriptions thereof will be omitted. In addition, the firstlight emitting units 222 and the second light emitting units 224 have asimilar structure to the structure described with reference to FIG. 4 orFIG. 5 , and thus, repeated descriptions thereof will be omitted.

Referring to FIG. 9 , the first light emitting unit 222 may have a colortemperature of, for example, 6,500K, and the second light emitting unit224 may have a color temperature of, for example, 2,700K. With the lightemitting units 222, 224 having color temperatures of 6,500K and 2,700K,respectively, the light emitting apparatus 200 can implement lightcorresponding to the spectrum of sunlight at noon and lightcorresponding to the spectrum of sunlight in the morning or evening.

Furthermore, the first light emitting unit 222 having a colortemperature of 6,500K and the second light emitting unit 224 having acolor temperature of 2,700K may be operated in a dimming manner, therebyimplementing light having different correlated color temperaturesbetween 6,500K and 2,700K. For example, light having a color temperatureof 4,000K may be implemented by operating the first light emitting units222 having a color temperature of 6,500K and the second light emittingunits 224 having a color temperature of 2,700K.

According to the illustrated exemplary embodiment, the number of typesof the light emitting units can be reduced, thereby simplifying theoperation of the light emitting apparatus.

FIG. 10 is a schematic color coordinate graph of a light emittingapparatus according to another exemplary embodiment. The light emittingapparatus according to the illustrated exemplary embodiment includesthree types of light emitting units, that is, first to third lightemitting units 322, 324, 326, which may be arranged on the base 110, asdescribed with reference to FIG. 3 .

As described above, each of the light emitting units 322, 324, 326includes a UV light emitting diode chip, a violet light emitting diodechip, or a blue light emitting diode chip, and a wavelength converteradapted to convert the wavelength of light emitted from the lightemitting diode chip. In an exemplary embodiment, each of the first lightemitting unit 322 and the second light emitting unit 324 may include theUV light emitting diode chip or the violet light emitting diode chip,and the third light emitting unit 326 may include the UV light emittingdiode chip, the violet light emitting diode chip, or the blue lightemitting diode chip. However, the color coordinates of the lightemitting units 322, 324, 326 according to the illustrated exemplaryembodiment are different from those described with reference to FIG. 7 ,and are set using the light emitting diode chips and the wavelengthconverter. Hereinafter, features of the light emitting apparatusaccording to the illustrated exemplary embodiment will be mainlydescribed.

In the illustrated exemplary embodiment, the first light emitting unit322, the second light emitting unit 324, and the third light emittingunit 326 are disposed to implement light having a color temperature inthe range of 3,000K to 5,000K on the Planckian locus. Unlike theexemplary embodiment shown in FIG. 7 , the first to third light emittingunits 322, 324, 326 are not required to exhibit the color coordinates onthe Planckian locus.

The first light emitting unit 322 may have color coordinates closer to acolor temperature of 5,000K than the second and third light emittingunits 324, 326, and the third light emitting unit 326 may have colorcoordinates closer to a color temperature of 3,000K than the first andsecond light emitting units 322, 324. In an exemplary embodiment, thefirst light emitting unit 322 may have a color temperature of 5,000K andthe third light emitting unit 326 may have a color temperature of3,000K, for example.

The second light emitting unit 324 has color coordinates placed abovethe Planckian locus in the CIE-1931 color coordinate system. Inparticular, the x-coordinate of the second light emitting unit 324 maybe placed within the x-coordinate range between a color temperature of5,000K and a color temperature of 3,000K on the Planckian locus.

Furthermore, any of a straight line connecting the color coordinates ofthe first light emitting unit 322 to the color coordinates of the secondlight emitting unit 324, a straight line connecting the colorcoordinates of the second light emitting unit 324 to the colorcoordinates of the third light emitting unit 326, and a straight lineconnecting the color coordinates of the first light emitting unit 322 tothe color coordinates of the third light emitting unit 326 may not crossa region between 5,000K and 3,000K on the Planckian locus. Moreparticularly, a triangle region is defined by the color coordinates ofthe first to third light emitting units 322, 324, 326, and a curvedportion between the color temperature of 5,000K and the colortemperature of 3,000K on the Planckian locus is placed in the triangleregion. In another exemplary embodiment, the straight line connectingthe color coordinates of the first light emitting unit 322 to the colorcoordinates of the second light emitting unit 324 may pass the colortemperature of 5,000K, and the straight line connecting the colorcoordinates of the second light emitting unit 324 to the colorcoordinates of the third light emitting unit 326 may pass the colortemperature of 3,000K. In addition, the straight line connecting thecolor coordinates of the first light emitting unit 322 to the colorcoordinates of the third light emitting unit 326 may pass the colortemperature of 5,000K or the color temperature of 3,000K.

According to the illustrated exemplary embodiment, the first to thirdlight emitting units 322, 324, 326 are operated in a dimming manner,thereby implementing light having any color temperature in the range of3,000K to 5,000K on the Planckian locus. Furthermore, since none of thefirst to third light emitting units 322, 324, 326 include a blue lightemitting diode chip, the light emitting apparatus can prevent emissionof light having abnormally high intensity in the blue wavelength region.

The light emitting apparatus according to the illustrated exemplaryembodiment may implement a maximum color temperature CTmax of 5,000K ormore through selection of the first light emitting unit 322 and thesecond light emitting unit 324, and a minimum color temperature CTmin of3,000K or less through selection of the second light emitting unit 324and the third light emitting unit 326.

The color temperatures of 3,000K and 5,000K are minimum requirements tocorrespond to change in spectrum of light for a day. Within this rangeof color temperature, the light emitting apparatus can emit lightcorresponding to change in spectrum of sunlight.

In order to implement light further similar to sunlight, the maximumcolor temperature CTmax may be further increased and the minimum colortemperature CTmin may be further decreased. For example, the maximumcolor temperature CTmax may be 6,000K or more, specifically 6,500K ormore, more specifically 10,000K or more. In addition, the minimum colortemperature CTmin may be 2,700K or less, specifically 1,800K or less.

The first light emitting unit 322 has the same x-coordinate as, or asmaller x-coordinate than, the x-coordinate of the color coordinatescorresponding to the maximum color temperature CTmax in a colortemperature range to be implemented thereby; the second light emittingunit 324 has an x-coordinate in a color temperature range to beimplemented thereby; and the third light emitting unit 326 has the samex-coordinate as, or a greater x-coordinate than the x-coordinate, of thecolor coordinates corresponding to the minimum color temperature CTminin a color temperature range to be implemented thereby.

For example, FIG. 11 is a schematic color coordinate graph of a lightemitting apparatus capable of implementing a color temperature in therange of 1,800K to 10,000K on the Planckian locus. The first lightemitting unit 322 has the same x-coordinate as or a smaller x-coordinatethan an x-coordinate of the color temperature of 10,000K; the secondlight emitting unit 324 has an x-coordinate of a color temperature inthe range of 1,800K to 10,000K; and the third light emitting unit 326has the same x-coordinate as or a greater x-coordinate than anx-coordinate of the color temperature of 1,800K. On the other hand, they-coordinate of the second light emitting unit 324 is set such, that thecolor coordinates of the second light emitting unit 324 are placed abovethe Planckian locus. In addition, the y-coordinate of each of the firstlight emitting unit 322 and the third light emitting unit 326 is setbetween 0 and 1, such that the triangle region defined by the colorcoordinates of the first to third light emitting units 322, 324, 326include the Planckian locus between the color temperature of 1,800K andthe color temperature of 10,000K.

In the illustrated exemplary embodiments of FIG. 10 and FIG. 11 , thecolor temperatures on the Planckian locus may be implemented byoperating the first to third light emitting units 322, 324, 326 in adimming manner. Accordingly, the light emitting apparatus according toexemplary embodiments can implement all color temperatures ranging fromthe minimum color temperature CTmin to the maximum color temperatureCTmax. A color temperature excluding the maximum color temperature CTmaxand the minimum color temperature CTmin may be implemented by operatingeach of the three types of light emitting units 322, 324, 326. Themaximum color temperature CTmax may be implemented by the first lightemitting unit 322 or through combination of the first light emittingunit 322 and the second light emitting unit 324, combination of thefirst light emitting unit 322 and the third light emitting unit 326, orcombination of the first to third light emitting units 322, 324, 326,and the minimum color temperature CTmin may be implemented by the thirdlight emitting unit 326 or through combination of the second lightemitting unit 324 and the third light emitting unit 326, combination ofthe first light emitting unit 322 and the third light emitting unit 326,or combination of the first to third light emitting units 322, 324, 326.In this manner, most color temperatures can be implemented by operatingeach of the three types of light emitting units 322, 324, 326 in adimming manner. In the light emitting apparatus described reference withto FIG. 7 , some light emitting units stop to operate and are on standbyto implement a particular color temperature. However, in the illustratedexemplary embodiment, each of the light emitting units may be operated,thereby enabling reduction in the number of light emitting units for aluminaire.

On the other hand, as described with reference to FIG. 3 , the first tothird light emitting units 322, 324, 326 may be repeatedly arranged in arow on the base 310. However, the inventive concepts are not limitedthereto, and the light emitting units may be arranged in various ways.FIG. 12 to FIG. 14 show light emitting apparatuses 300, 400, 500, inwhich the first to third light emitting units 322, 324, 326 are arrangedon the base 310 in various ways. Hereinafter, the base 310 is similar tothe base 110 described with reference to FIG. 3 , and thus, repeateddescriptions thereof will be omitted.

Referring to FIG. 12 , the first to third light emitting units 322, 324,326 according to an exemplary embodiment may be arranged in a matrix.For example, the first light emitting units 322 may be arranged in afirst line, the second light emitting units 324 may be arranged in asecond line adjacent thereto, and the third light emitting units 326 maybe arranged in a third line adjacent to the second line. Further, thefirst to third light emitting units 322, 324, 326 may be arrangedtogether in the same row.

Referring to FIG. 13 , the first light emitting unit 322, the secondlight emitting unit 324, and the third light emitting unit 326 accordingto another exemplary embodiment may be arranged as one group in atriangular shape, and groups of these light emitting units may berepeated in the same way. According to the illustrated exemplaryembodiment, the light emitting apparatus 400 can emit more uniform lightthan the light emitting apparatus 300 shown in FIG. 12 .

Referring to FIG. 14 , the first light emitting unit 322, the secondlight emitting unit 324, and the third light emitting unit 326 accordingto yet another exemplary embodiment may be arranged as one group in atriangular shape, and groups of these light emitting units may berepeated in an alternating way. More specifically, a group of the firstto third light emitting units adjacent to the group of the first tothird light emitting units arranged in a triangular shape has aninverted triangular shape. In this manner, the distance between the sametypes of light emitting units may be constant. For example, each of adistance between the first light emitting units 322, a distance betweenthe second light emitting units 324, and a distance between the thirdlight emitting units 326 may be constant. Accordingly, the lightemitting apparatus 500 can emit more uniform light than the lightemitting apparatus 400 of FIG. 13 .

FIG. 15 is a schematic color coordinate graph of a light emittingapparatus according to yet another exemplary embodiment.

Referring to FIG. 15 , the light emitting apparatus according to theillustrated exemplary embodiment includes first to fourth light emittingunits 422, 424, 426, 428. Each of the first to fourth light emittingunits 422, 424, 426, 428 includes a UV, violet or blue light emittingdiode chip, and a wavelength converter.

A rectangular region is defined by the color coordinates of the first tofourth light emitting units 422, 424, 426, 428, and a demanded Planckianlocus is placed in the rectangular region. With this structure, thelight emitting apparatus can implement all of color temperatures on thePlanckian locus placed in the rectangular region through combination ofthe first to fourth light emitting units 422, 424, 426, 428.

In particular, the first light emitting unit 422 may have colorcoordinates near a color temperature of 10,000K, and the second lightemitting unit 424 may have color coordinates placed above the Planckianlocus in the CIE-1931 coordinate system. Each of the third lightemitting unit 426 and the fourth light emitting unit 428 may have colorcoordinates near a color temperature of 1,800K, in which the colorcoordinates of the third light emitting unit 426 may be placed above thePlanckian locus and the color coordinates of the fourth light emittingunit 428 may be placed below the Planckian locus.

In the illustrated exemplary embodiment, in order to reduce theintensity of blue light emitted from the blue light emitting diode chip,the first and second light emitting units 422, 424 may employ a UV orviolet light emitting diode chip, instead of the blue light emittingdiode chip. Even with the blue light emitting diode chip, the third andfourth light emitting units 426, 428 emit low intensity blue light, andthus, may not damage the retina. Accordingly, the third and fourth lightemitting units 426, 428 may include any light emitting diodes selectedfrom among the UV, violet, and blue light emitting diode chips, asdesired.

According to the illustrated exemplary embodiment, the light emittingapparatus can implement a color temperature in the range of 1,800K to10,000K. However, the inventive concepts are not limited thereto, and insome exemplary embodiments, the first to fourth light emitting units422, 424, 426, 428 may be set to implement a color temperature in therange of, for example, 3,000K to 5,000K or more.

FIG. 16 is a graph depicting spectrum power distributions of first tothird light emitting units according to an exemplary embodiment, andFIG. 17 to FIG. 28 are graphs comparing various spectra implementedusing the light emitting units of FIG. 16 with the spectrum of blackbody radiation (reference light source) at correlated color temperaturescorresponding thereto.

Each of the first to third light emitting units according to anexemplary embodiment includes violet light emitting diode chips having apeak wavelength of about 416 nm. Further, the first light emitting unitincludes a blue phosphor, a green phosphor, a yellow phosphor, and a redphosphor, and has color coordinates (x, y) of (0.2638, 0.2756), acorrelated color temperature of 13,597K and Duv of 0.0043. The secondlight emitting unit includes a blue phosphor, a green phosphor, a yellowphosphor, and a red phosphor, and has color coordinates (x, y) of(0.3860, 0.4354), a correlated color temperature of 4,222K and Duv of0.0236. The third light emitting unit includes a blue phosphor, a greenphosphor, a yellow phosphor, and a red phosphor, and has colorcoordinates (x, y) of (0.5439, 0.4055), a correlated color temperatureof 1,822K and Duv of 0.000.

By operating the first to third light emitting units in a dimmingmanner, it is possible to implement various color temperatures in therange of 1,800K to 10,000K. FIG. 17 to FIG. 18 are graphs comparingvarious spectra implemented using the first to third light emittingunits of FIG. 16 with the spectrum of the reference light source atcorrelated color temperatures corresponding thereto.

Referring to FIG. 17 to FIG. 28 , it can be confirmed that the spectrumat various color temperatures implemented by the first to third lightemitting units generally matches with the spectrum by black bodyradiation in the visible spectrum region. In particular, it can beconfirmed that, even at a high color temperature, the intensity of lightin the blue wavelength region is not abnormally higher than theintensity of light in other color regions.

Table 2 shows average color rendering indices CRI and fidelity indicesat various color temperatures implemented by the first to third lightemitting units.

TABLE 2 CRI and fidelity indices of light emitting apparatus accordingto an exemplary embodiment. CCT CRI Rf 10000K  96.2 96.9 6500K 97.6 98.15700K 98.3 98.3 5000K 97.3 98.2 4500K 97.4 97.5 4000K 97.4 97.4 3500K95.6 96.8 3000K 95.6 96.4 2700K 95.2 95.9 2500K 95.6 94.8 2200K 95.094.6 1800K 94.3 91.8

Referring to Table 2, not only high CRI but also high Rf can bemaintained by implementing the color temperature through combination ofthe first to third light emitting units, thereby implementing lightsimilar to sunlight.

In addition, when the color temperature in a preset range is implementedusing each of the first to third light emitting units, it is possible toreduce the number of light emitting units in actual use under the samepower consumption. This will be described in more detail below. In orderto compare various exemplary embodiments with each other, a drivevoltage and a power of each of the light emitting units were set to 3 Vand 27 W, respectively.

First, as in the exemplary embodiment described with reference to FIG. 7, when three types of light emitting units 122, 124, 126 respectivelycorresponding to the above color temperatures are operated at aconsumption power of 27 W in a switching on/off manner, 90 lightemitting units are used for each color temperature. For example, 90first light emitting units 122 are operated to implement a colortemperature of 6,500K; 90 second light emitting units 122 are operatedto implement a color temperature of 4,000K; and 90 third light emittingunits 126 are operated to implement a color temperature of 2,700K. Inaddition, during operation of one type of light emitting unit, forexample, the first light emitting units 122, other light emitting units,for example, the second and third light emitting units 124, 126, arekept in a standby state.

Accordingly, for operation at a consumption power of 27 W, a total of270 light emitting units is required and only 90 light emitting unitsare operated. On the other hand, in the exemplary embodiment illustratedwith reference to FIG. 7 , when three types of light emitting units 122,124, 126 are operated in a dimming manner, among the total of 270 lightemitting units, 180 light emitting units may be operated and 90 lightemitting units may be kept in a standby state.

In the exemplary embodiment described with reference to FIG. 9 , whentwo types of light emitting units 222, 224 are operated at a consumptionpower of 27 W in a switching on/off drive manner, 90 light emittingunits are used for each color temperature. As such, desired colortemperatures can be implemented by a total of 180 light emitting units.In this case, it is difficult to implement a color temperature in therange of, for example, 6,500K to 2,700K on the Planckian locus, andlight having color coordinates placed below the Planckian locus isemitted.

When all of the first to third light emitting units 322, 324, 326 areoperated at a consumption power of 27 W in a dimming manner to obtaindesired color temperatures, for example, 60 light emitting units may beused for each color temperature. As such, desired color temperatures canbe implemented using a total of 180 light emitting units.

Further, when the first light emitting unit 322 or the third lightemitting unit 326 has the same color coordinates as those of a colortemperature to be implemented thereby, the number of first lightemitting units 322 or the number of second light emitting units 326 usedto implement the color temperature may be 90. Even in this case, only 60second light emitting units 324 may be used, thereby allowing reductionin the number of light emitting units, as compared with the switchingon/off drive manner of FIG. 6 .

FIG. 29 is a schematic block diagram of a lighting system 1000 accordingto an exemplary embodiment.

Referring to FIG. 29 , the lighting system 1000 may include a lightingapparatus 1100 and an electronic control unit 1200 for operation of thelighting apparatus.

The lighting apparatus 1100 includes a controller 1110, an LED driver1130, and an LED luminaire 1150. The electronic control unit 1200 mayinclude a remote controller 1210, a mobile application 1230, a personalcomputer (PC) or server 1250, or the like. In some exemplaryembodiments, the electronic control unit may be a software.

The LED luminaire 1150 includes the light emitting apparatus accordingto the exemplary embodiments described above, and thus, can implementlight having various color temperatures. As such, repeated descriptionsof the light emitting apparatus will be omitted to avoid redundancy.

The electronic control unit 1200 sends a signal to operate the lightingapparatus 1100, and the controller 1110 operate the LED driver 1130 inresponse to the signal sent from the electronic control unit 1200. Then,the LED driver 1130 operates the light emitting units in the LEDluminaire 1150 to emit light having a certain color temperature andbrightness. The LED driver 1130 may operate the light emitting units ina dimming manner through pulse width modulation.

The electronic control unit 1200 may change the color temperature oflight emitted from the LED luminaire 1150 depending upon time bychanging the signal sent therefrom. Accordingly, the electronic controlunit 1200 can change the color temperature of light emitted from the LEDluminaire 1150 to the same color temperature as the color temperature ofsunlight during daytime.

For example, the remote controller 1210 may send an input signal to thecontroller 1110. The controller 1110 receives the signal through awireless communication module and drives the LED driver 1130 in responseto the signal from the remote controller 1210. The signal may betransferred to the controller 1110 through the mobile application 1230or through the PC or server 1250. In some exemplary embodiments, the PCor the server 1250 may receive the controller 1110 therein, and the LEDdriver 1130 may be driven through wired or wireless communication.

According to the illustrated exemplary embodiment, the color temperatureand brightness of the LED luminaire 1150 may be controlled outside thelighting apparatus 1100 by a user inputting a control signal through theremote controller 1210, the mobile application 1230, or the server 1250.

Although the lighting apparatus 1100 is described as changing the colortemperature and brightness of the LED luminaire 1150 through theelectronic control unit 1200, the color temperature and brightness ofthe LED luminaire 1150 may be directly changed by a user throughmanipulation of a switch connected to the controller 1110 through awire, or may be changed through a sensor provided to the LED luminaire1150.

FIG. 30 is a schematic block diagram of a lighting system 2000 accordingto another exemplary embodiment.

Referring to FIG. 30 , the lighting system 2000 according to theillustrated exemplary embodiment includes a lighting apparatus 2200 andan electronic control unit 2100 for operation of the lighting apparatus2200.

The lighting apparatus 2200 includes a controller 2110, an LED driver2130, an LED luminaire 2150, and a memory 217. The electronic controlunit 2100 may include a remote controller 2210, a mobile application2230, a personal computer (PC) or server 2250, and the like.

The lighting system 2000 according to the illustrated exemplaryembodiment is generally similar to the lighting system 1000 shown inFIG. 29 , and thus, repeated description of the same components will beomitted to avoid redundancy. The following descriptions will be focusedon different features of the lighting system according to theillustrated exemplary embodiment.

Unlike the lighting system of FIG. 29 , the controller 2110 of thelighting system 2000 includes a real time clock (RTC). The RTC may beincluded in the form of an integrated circuit in the controller 2110.Since the controller 2110 includes the RCT, a control module 2110 maycontrol the LED luminaire 2150 according to a schedule without receivingan external signal.

For example, the color temperature and brightness of sunlight accordingto time in each season may be stored in the memory 2170, and thecontroller 2110 may control the light emitting apparatus 2200 in the LEDluminaire 2150 through the RTC to emit light having a similar colortemperature and brightness to the color temperature and brightness ofsunlight according to time in each season. Accordingly, the LEDluminaire 2150 may illuminate an indoor space while changing the colortemperature corresponding to change in the color temperature of sunlightduring daytime.

Table 3 shows one example of a scenario of a color temperature changeaccording to time in each season using the LED luminaire 2150 configuredto emit light having a color temperature in the range of 2,200K to6,500K. The color temperature was set to maintain at 2,200K after sunsetand to change to a color temperature similar to the color temperature ofsunlight during daytime. Table 3 shows one example of a colortemperature change depending on time, and such a color temperaturechange depending on time may be arbitrarily set.

TABLE 3 Color temperature scenario in each season. Season time SpringSummer Autumn Winter 0 2200K 2200K 2200K 2200K 1 2200K 2200K 2200K 2200K2 2200K 2200K 2200K 2200K 3 2200K 2200K 2200K 2200K 4 2200K 2700K 2200K2200K 5 2700K 3500K 2700K 2200K 6 3500K 3500K 3500K 2700K 7 3500K 3500K3500K 3500K 8 3500K 3500K 3500K 3500K 9 3500K 3500K 3500K 3500K 10 3500K3500K 3500K 3500K 11 3500K 3500K 3500K 3500K 12 6500K 6500K 6500K 6500K13 6500K 6500K 6500K 6500K 14 6500K 6500K 6500K 6500K 15 6500 6500K6500K 6500K 16 6500K 6500K 6500K 6500K 17 6500K 6500K 6500K 2700K 182700K 6500K 2700K 2500K 19 2500K 2700K 2500K 2300K 20 2300K 2500K 2300K2200K 21 2200K 2300K 2200K 2200K 22 2200K 2200K 2200K 2200K 23 2200K2200K 2200K 2200K

In addition, although the color temperature is set to change every hourin Table 1, the color temperature may be set to change every 30 minutes,10 minutes, or several minutes.

According to the illustrated embodiment, since the RTC is embedded inthe lighting apparatus 2200, the lighting apparatus 2200 mayautomatically change the color temperature corresponding to the colortemperature of sunlight without the electronic control unit 2100.Accordingly, even when the electronic control unit 2100 is in aturned-off state, the lighting apparatus 2200 can automatically changethe color temperature and brightness.

The lighting apparatus 2200 may be operated in various modes, which maybe selected through the electronic control unit 2100. For example,control of the color temperature using the RTC may be selected throughthe remote controller 2210, the mobile application 2230, or the PC orserver 2250. In addition, in a particular mode, the lighting apparatus2200 may be controlled through the electronic control unit 2100, or maybe manually controlled through a switch. The controller 2110 may includea wireless communication module to receive signals sent from the soelectronic control unit 2100.

Human biorhythms are different according to age, and thus, according toan exemplary embodiment, an illumination mode may be set to implementlighting optimized for biorhythms according to age. For example, personsmay be divided into age groups including infancy, childhood,adolescence, and adulthood, and lighting time zones of cool white andwarm white may be differently adjusted.

FIG. 31 is a schematic block diagram of a lighting system 3000 accordingto a further exemplary embodiment.

Referring to FIG. 31 , the lighting system 3000 according to theillustrated exemplary embodiment is similar to the lighting system 2000of FIG. 30 , except that the lighting system 3000 further includes anRTC power supply 2190 supplying power to the RTC.

The lighting apparatus 2100 may be operated by power supplied from anexternal power source (or main power source). The RTC may receive powersupplied from the external power source. Here, when the external powersource is blocked in order to turn off the LED luminaire 2150 or due toan abnormal condition, power supply to the RTC is blocked. In this case,the RTC cannot be normally operated and fails to recognize the time.Then, even when power is supplied again thereto from the external powersource, the RTC is not operated in association with an actual timeprogress. As such, the lighting apparatus 2100 cannot change the colortemperature in real time in association with change in color temperatureof sunlight.

The RTC power supply 2190 prevents the RTC from being turned off bysupplying power to the RTC when the external power source or the mainpower source is blocked. In this manner, the RTC can keep the actualtime progress.

The RTC power supply 2190 is connected to the RTC in the lightingapparatus 2100 to supply power to the RTC. The RTC power supply 2190 maybe connected to the RTC to be charged with the external power sourceturned on and to be discharged with the external power source blocked.

The RTC power supply 2190 may be, for example, a primary battery or asecondary battery. For example, the RTC power supply 2190 may be alithium battery or a lithium ion battery.

Although the primary battery does not require a separate charge circuit,the primary battery has relatively short lifespan, and thus, may requirefrequent replacement depending upon lifespan thereof.

On the other hand, although the secondary battery allows charge anddischarge, and thus, does not require frequent replacement, thesecondary battery has a restricted operation temperature. Generally, thelighting apparatus 2100 is driven for a long period of time and theinterior temperature of the lighting apparatus 2100 can reach 60° C. ormore. However, since the secondary battery is not suitable for use at atemperature of 60° C. or more, the secondary battery cannot be used inthe lighting apparatus 2100 which is used for a long period of time.

According to an exemplary embodiment, the RTC power supply 2190 may be asuper capacitor. The super capacitor is operated at a temperature ofabout −40° C. to 85° C., and is thus suitable for operation conditionsof the lighting apparatus 2100. In addition, the super capacitor hasmuch longer lifespan than the primary battery or the secondary battery,and can be charged by an external power source. Thus, the supercapacitor does not require replacement.

Although some embodiments have been described herein, it should beunderstood by those skilled in the art that these embodiments are givenby way of illustration only and that various modifications, changes, andalterations can be made without departing from the spirit and scope ofthe present disclosure. In addition, individual structures, elements, orfeatures of a particular embodiment can be applied to other embodimentswithout departing from the spirit and scope of the present disclosure.

What is claimed is:
 1. Alighting apparatus comprising: a controller; and an LED luminaire configured to implement a color temperature from a minimum color temperature of 3,000K or less to a maximum color temperature of 5,000K or more, the LED luminaire comprising a light emitting apparatus including at least one first light emitter, at least one second light emitter, and at least one third light emitter, wherein the controller is configured to control the first, second, and third light emitters to change the color temperature of the LED luminaire, wherein a triangle region defined by color coordinates of the first light emitter, the second light emitter, and the third light emitter comprises at least a region on a Planckian locus, and the maximum color temperature and the minimum color temperature included in the triangle region are 5,000K or more, and 3,000K or less, respectively, wherein in the CIE-1931 coordinate system, the color coordinates of the at least one first light emitter is closer to a color temperature of 5,000K than those of the at least one second light emitter and the at least one third light emitter, and the color coordinates of the at least one third light emitter is closer to a color temperature of 3,000K than those of the at least one first light emitter and the at least one second light emitter. 